System and Method of Automatically Mapping a Given Annotator to an Aggregate of Given Annotators

ABSTRACT

A document corpus is annotated by given annotators and aggregates of the given annotators to generate a corpus of pre-annotated documents with given annotations. The same document corpus is annotated by a subject annotator to have subject annotations. The subject annotations are decomposed into superpositions of the given annotations. The decomposed subject annotations are mapped to a most representative superposition of the given annotations. The subject annotator may be mapped to the aggregate of given annotators corresponding to the most representative superposition.

FIELD OF THE INVENTION

The field of the invention is data processing of documents, morespecifically, mapping a given annotator to an aggregate of otherannotators in a given knowledge domain.

BACKGROUND OF THE INVENTION

Text analysis, referenced hereinafter as “TA,” is known in the artpertaining to this invention as a sub-area or component of NaturalLanguage Processing, hereinafter referenced as “NLP.” TA is used in arange of commercial, research and educational industries and usesincluding, for example, information search and retrieval systems,e-commerce and e-learning systems. A typical TA involves an “annotator”which, as known in the relevant art, is a process for searching andanalyzing text documents using a defined set of tags, and running theannotator on the text document to generate what is known in the art as“linguistic annotations.” Annotators and linguistic annotations are wellknown. For the interested reader, an example listing of the manyavailable TA publications can be found at the following URL:<http://www.Idc.upenn.edu/>.

An example TA may be illustrated by: <annot type=“X”>text</annot>, where“X” may be any of a defined set of annotation types such as, forexample, Person, Organization and Location, and “text” is the text thatthe “X” annotation characterizes. This example TA, when inserted into orotherwise associated with an example text to indicate or delineate thebeginning and end of the annotated text, may be as follows:

-   -   “The underlying economic fundamentals remain sound as has been        pointed out by the Fed,” said <annot type=“Person”>Alan        Gayle</annot>, a managing director of <annot        type=“Organization”>Trusco Capital Management</annot> in <annot        type=“Location” kind=“city”>Atlanta</annot>, “though        fourth-quarter growth may suffer”.

In the above example, “Alan Gayle” is an instance of the annotation typePerson, “Trusco Capital Management” is an instance of the annotationtype Organization and “Atlanta” is an instance of the annotation typeLocation. The example annotation type Location has an example feature,shown as “kind,” with example possible values of “city”, “state”, andthe like.

A problem can exist or present, though, when using a new or unknownannotator, which is that the industrial fields or other TA objectives towhich the unknown annotator relates, to which it may be best suited, maynot be fully known.

These and other problems can be considerable, because a user often needsa particularly tailored application, e.g. particular annotation rulesand annotation types (e.g. annotate all CEOs of IT companies), indocuments from in a given document collection or domain. There are knownways of building such particularly tailored applications, such as, forexample, Interactive Learning System (see, for instance, SAILsystem—http://www.research.ibm.com/IE/). These related art systems caneventually generate a rule-based annotation engine, capable of producingdesired annotations, but have at least two shortcomings: human judgmentis required, and there is a possibility of producing or converging on aninefficient result. For example, there may be a high number ofprocessing rules generated by the SAIL system in response tointeractions with the human user. Further, a new knowledge domain, andeven a new document corpus, may require re-training of the system andre-generating the rules.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a method andapparatus for mapping an annotator to a best aggregate of a collection'sannotators.

Another object of the invention is to provide a method and apparatusthat, based on a given corpus of documents, and a given collection ofknown annotators, identifies whether there exists an aggregate of theknown annotators that is a functional equivalent to an unknownannotator.

Another object of the invention is to provide a method and apparatus forreplacing a plurality of annotators in an annotation processing pipewith one, potentially more efficient, aggregate of known annotators.This object particularly relates to certain objects of TA, in thatanalysis application often involves a large set of annotators that formthe annotation processing pipe.

A general embodiment of the invention includes a given collection ofannotators and a subject annotator. The annotators in the givencollection may include annotators that are non-aggregated, i.e.,primitive annotators, and/or annotators that are themselves aggregatesof other annotators. The subject annotator may be a known annotator, ormay be an unknown annotator, but in both cases it is analyzed as a blackbox.

A general embodiment performs steps, or includes machine-readableinstructions, for identifying whether the subject annotator isfunctionally equivalent to an aggregate of the given annotators and, ifsuch a functionally equivalent aggregate is identified. If afunctionally equivalent aggregate is found by the embodiment to exist,it a general embodiment performs steps, or includes machine readableinstructions, for mapping the subject annotator to the identifiedvirtual aggregate of collection's annotators.

A general embodiment identifies whether the subject annotator includesproviding a corpora of original documents and providing or generating acorresponding corpora annotated documents. The original documents areselected or provided such that the corpora of annotated documentscontains instances of annotations produced by all of the collection'sannotators and by all of annotators' possible aggregates.

A general embodiment further includes applying the subject annotator tothe corpus of original documents to produce instances of its annotationsin all documents.

A general embodiment further may include sorting-out good candidateannotations, from the set of annotations produced by annotators from thegiven collection, and decomposing annotations produced by the subjectannotator, to represent them as superpositions of the given candidateannotations, on a per document group basis.

A general embodiment further includes mapping the subject annotator to avirtual or actual aggregate of the given annotators in the selects, andthe mapping may include selecting the most representative superpositionof the given candidate annotations and then mapping that superpositionit to a virtual or actual aggregate of the collection's givenannotators.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example detailed system architecture in accordancewith at least one embodiment;

FIG. 2 illustrates an example high level flow diagram of an exampleannotator mapping system and method according to the present invention;

FIG. 3 illustrates, in graph representation form, an example of aselection of good candidate annotations from the given annotations inthe FIG. 2 example annotator mapping system and method; and

FIG. 4 illustrates an example flow diagram of a decomposition of asubject annotation into a logical expression of given annotations.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

It is to be understood that the present invention is not limited to thespecific examples described herein and/or depicted by the attacheddrawings, and that other configurations and arrangements embodying orpracticing the present invention can, upon reading this description, bereadily implemented by persons skilled in the arts pertaining to theinvention.

In the drawings, like numerals appearing in different drawings, eitherof the same or different embodiments of the invention, referencefunctional or system blocks that are, or may be, identical orsubstantially identical between the different drawings.

It is to be understood that the various embodiments of the invention,although different, are not necessarily mutually exclusive. For example,a particular feature, function, act or characteristic described in oneembodiment may, within the scope of the invention, be included in otherembodiments.

Further, it is to be understood that the terminology used herein is notlimiting and, instead, is only for purposes of ease of reference.

Further, it is to be understood that functions and operations shown ordescribed as separate blocks are not, unless otherwise specified orclear from the context, necessarily performed at separate times, or onseparate computational units, and operations described or depicted asbeing separate may be implemented or modeled as a single block.

Further, as will be understood by persons skilled in the art uponreading this description, certain well-known methods, arrangements, actsand operations of annotators are omitted, or are not described indetail, so as to better focus on, and avoid obscuring the novelfeatures, combinations, and structures of the present invention.

The present invention includes various functional blocks, acts, stepsand/or operations (collectively “operations”), which will be describedbelow. The operations can be embodied in machine-executableinstructions, which may be stored on a machine-readable medium, whichcan be used to cause a general-purpose or special-purpose processorprogrammed with the instructions to perform the operations.

FIG. 1 illustrates one example of a detailed system architecture 10 inaccordance with at least one embodiment, in which described operationscan be embodied in machine-executable instructions stored on, forexample, the disk 12 or other machine-readable medium, the instructionscausing a general-purpose or special-purpose processor, such as, forexample, the central the processing unit, or CPU 14 to perform theoperations. The instructions may be stored on, for example, the disk 12or another other storage medium. The described data and annotatorsystems, such as the corpus of documents, pre-annotated documents andannotated documents, given annotators and subject or unknown annotatordescribed in reference to FIGS. 2-4, may be stored on, for example, thedisk 12 or another machine medium. An I/O unit or system 16 such as, forexample, a keyboard and/or graphical user interface or, for example, apersonal computer connected via network to the CPU 14 is included in theexample system 10.

Alternatively, the described operations may be performed by specifichardware components that contain hardwired logic for performing thesteps, or by any combination of programmed computer components andcustom hardware components. Further, the described operations may beperformed in distributed computing systems or environments, such asprocessors and processing components remote from a machine-readablemedium, where instructions from the medium are communicated over acommunication link or network.

Example General Flow and System Overview

A collection of given annotators is provided. For purposes of thisdescription, an annotator is a process, method or routine that inserts,adds or associates annotations to textual media documents. The givenannotators may include primitive annotators and aggregate annotators,where primitive annotator means a species of annotator that itselfcarries out annotator processes methods or routines, without using otherannotators and aggregate annotators, or aggregates, means a species ofannotator composed of a plurality of other annotators, which themselvesmay be primitive and/or aggregate annotators. An aggregate is defined asa flow of annotators constituting the aggregate operation flow.

All possible aggregates of the given annotators are also provided in thecollection, or are generated using, for example, conventional methods oralgorithms for aggregating annotators. A corpora of original documentsis provided, and a corresponding corpora of annotated documents isprovided or generated. The annotated documents are the originaldocuments annotated to contain instances of annotations produced by allof the collection's given annotators and by all aggregates of the givenannotators. These instances are referenced in this description as “givenannotations.” The subject annotator is applied to the corpus of originaldocuments to produce instances of its annotations in all documents.These instances are referenced in this description as “subjectannotations.”

A filtering may be performed, to reduce unnecessary computational burdenin subsequently described operations, to sort out annotations from thegiven annotations using a described method of calculating theirrelevance, these filtered annotations being collectively referenced inthis description as “good candidate annotations.”

The subject annotations are decomposed into a representation that is bysuperpositions of the given annotations. The decomposition is in termsof certain of the given annotations, which are either those sorted outas good candidate annotations, by the optional filtering or, inherent inthe decomposition, ones of the given annotations that would have beenidentified as good candidate annotations if the filtering wereperformed. The decomposition is on a per document group basis.

A mapping is performed that selects the most representativesuperposition of the given candidate annotations and maps thatsuperposition to a virtual or actual aggregate of collection'sannotators. This, in turn, provides automatic mapping any givenannotator to a virtual or actual aggregate of the given collection'sannotators.

An example overview of the decomposition of subject annotations into arepresentation as superpositions of the given annotations may berepresented as follows:

-   -   i. Represent annotations as mapping functions from the space of        documents and sentences to the space of tagged textual spans;    -   ii. Embed the space of equitagged spans into the vector space of        appropriate dimension. With this abstraction annotation        functions map the space of documents and sentences into the        vector space;    -   iv. Define Boolean expressions on the annotation spans;    -   v. Form a basis on the set of annotation expressions; and    -   vi. Identify an expression of the untried equitagged Annotation        through the given set of annotations.

Example Functional Flow

FIG. 2 illustrates an example functional flow diagram for an embodimentof the method.

At 102 a plurality of N annotators is provided, represented in FIG. 2 bythe sub-blocks labeled Annotator_(n), for n=1 to N. Also at 102, allaggregates of the annotators, Annotator_(n)n=1 to N, are provided orgenerated. The aggregates are represented at 102 of FIG. 2 asAggregate_(i), for i=1-2 . . . 1-N, 2-1 . . . 2-N . . . K-L-M . . . Thehyphenated value of the subscript i of Aggregate represents all of theAnnotator_(n) aggregated to form that Aggregate_(i). For example,Aggregate_(2-4-N) is the aggregate of the 102 given Annotator₂,Annotator₄ and Annotator_(N), and Aggregate₁₋₄₋₆ is the aggregate ofAnnotator₁, Annotator₄ and Annotator₆.

102 may be realized by providing all of the N annotators and all of theaggregates, or by providing all of the N annotators and then generatingall of the possible aggregates. As can be understood by persons ofordinary skill in the relevant arts, the above phrase “all of thepossible aggregates” means all reasonable aggregates that can be createdfrom the given annotators, where “reasonable” is associated with twogeneral conditions: (i) an input/output condition requiringcompatibility at the type system level, because annotators can beaggregated only if they have such compatibility; and (ii) a semanticcondition, requiring that the annotators be such that their aggregationis meaningful.

With continuing reference to FIG. 2, at 104 an original document corpusis provided.

At 106 a subject annotator, which may be an unknown annotator, or one ofthe given annotators, is applied to the original document corpus 104 togenerate a corpus of annotated documents 108.

At 110 each Annotator_(n), for n=1 to N, and each Aggregate_(i), fori=1-2 . . . 1-N, 2-1 . . . 2-N . . . K-L-M, is applied to the originaldocument corpus to generate a corpus of pre-annotated documents 112.

At 114, which is an option that may reduce unnecessary computationburden in carrying out the decomposing 116 described below, a sorting isperformed to sort out from the annotations contained in thepre-annotated documents 112 those annotations meeting a criteria forcorrelation, in terms of occurrences, with the subject annotations. Suchannotations are referenced in this description as “good candidateannotations.”

An example of the 114 filtering is illustrated in FIG. 3, as follows:

-   -   a) a graph, or information that can be described in graph form        is constructed or calculated for each concrete annotation type        of the given annotators, for each document in the pre-annotated        documents 112, representing frequencies of the candidate        annotation instances in each sentence of the document;    -   b) analogous frequency graphs, or frequency information that can        be described in graph form as graphs, are calculated or        constructed, for each document in the annotated documents 108,        for the subject annotation instances; and    -   c) by comparing, on a per document basis, the graphs or        information identified at sub-paragraph (a) above, i.e., the        given candidate annotations frequency graphs, to the graphs or        information identified at sub-paragraph (b) above, i.e., the        subject annotations frequency graphs, filtering is obtained as        to the given candidate annotations instances that have frequency        graphs correlated with the frequency graphs of the subject        annotations instances.

Referring again to FIG. 2, at 116 the subject annotations are decomposedinto aggregates of the given annotations.

FIG. 4 illustrates an example flow diagram for the 116 decomposition.Referring to FIG. 4, at 302 the annotations are formally modeled as amapping from a (corpus, document, sentence) space to a (span, tag)space. An example modeling identifies, as equitagged spans, the spanswith the same value of the tag. The measure on the spans may berepresented as follows: Span S is represented as the union ofnon-intersecting intervals I_(k) from the sentence associated with theannotation. For each interval I_(k)=[α_(k),α(_(k+1))], where α_(i) arecoordinates (positions) within the document, the measure may be definedas measure m(I_(k)) being |α_((k+1))−α_(k)|, and for the span themeasure may be defined as m(S)=Σm(I_(k)).

At 304 the spans are embedded into a vector space of dimensionpreferably greater or equal to the number of all possible spans for thissentence. For example, the sentence “The summit starts today.” can have4+6+3+1=14 spans, including non-contiguous spans.

An example of the embedding 304 is as follows:

Consider functions F from (corpus, document, sentence)->R^(d), whered=length_of(sentence).

Span-interval I_(k) corresponds to the vector space generated by thecoordinates [α_(k), α_((k+1))] and, with each span S defined as a unionof the non-intersecting intervals I_(k), we associate FS(S) as afunction from set of all functions from (corpus, document, sentence)->subspaces generated by appropriately taken coordinates of the R^(d).Regarding the “appropriately taken coordinates,” for this exampleembedding 304 the vector space dimension is equal to the number ofcharacters in the sentence, which is d generated by the above-describedfunctions F. The position of each character position this sentence maybe represented by the vector d, having a logical “1” coordinate in theposition corresponding to the position of the character in the sentenceand logical “0” coordinates in all other positions (like ‘100 . . . 0’for the 1^(st) character, etc.) In the same way, the embedding 304 mayassociate each word in the sentence with a sum of vectors representingits characters. Each span may include one or more words, so the ‘span’function can map the tuple (corpus, document, sentence) into subspacesof the R^(d) that include vectors corresponding to whole words or theircombinations. An example embedding 304 may fix a counting measure on(corpus, document, sentence), and define a scalar product on FS as (FS₁,FS₂)=Sum over all (corpus, document, sentence) of m(S1 intersect S2).

Referring to the FIG. 4 example functional flow, 306 maps the annotationexpression into, for example, a lattice of the possible expressions. Anexample 306 mapping may be as follows:

-   -   a. let annotation A_(i) correspond to the span S_(i);    -   b. define for two annotations, labeled for reference as A₁ and        A₂, an intersection operation S₀ as the coordinate-wise union of        all possible pairwise intersections of intervals defining S₁ and        S₂;    -   c. define a union operation S₀ of A₁ and A₂ in a similar manner        as (b). It should be noted that the union S₀ of S₁ and S₂ is a        union of spans coordinate wise;    -   d. define in a similar manner a complement of S₁ and inclusion        S₂ in S₁;    -   e. define, as possible Boolean expressions corresponding spans,        coordinate-wise, the set of all possible expressions of the        annotations A_(i); and    -   f. form the set of all possible expressions, referenced        hereinafter as APE, on the annotations A_(i) as a lattice LA        with respect to union, intersection, inclusion and complement.

It will be understood that the above-listed example outline for carryingout the example mapping 306 to a lattice is only for purposes ofpresenting an example logical representation, and is not necessarily arepresentation of a sequence, grouping or modules of operations ormachine-readable code for the mapping.

With continuing reference to FIG. 4, 308 extracts a basis on the set ofall possible expressions (APE). The basis may not be unique, but thedescribed system and method, and the processing results, do not dependon the specific extracted or chosen basis. An example 308 extractionchooses as the basis on the set of all possible expressions (APE) theminimal set of elements from inclusion APE (IAPE), in the sense that noelement is less than a given element with respect to inclusion, so thateach expression E from APE may be represented as a union of elementsfrom IAPE. A minimal set of elements is the smallest possible result,which is the intersection of all annotations. This may be an empty set.Identifying the basis may be, for example, generally along the flow ofGauss elimination for linear matrices. For example, extraction 308 mayiteratively remove indices, one at a time, and create an intersectionfor them. The iterations may be in accordance with, or carried outapplying the following logic:

-   -   i) The removed index may be empty, or it may be the first index        for which all possible further intersections will be empty. If        it is the first such index then it is a minimal set and it is        chosen.    -   ii) If the removed index is not the first non-empty index, then        the difference between this set and all possible chosen minimal        sets may be considered, and a complementary minimal set may be        chosen based on this difference.

It will be understood that the above-listed example outline for carryingout the example extraction 308 is for only for purposes of presenting anexample logical representation, and is not necessarily a representationof a sequence, grouping or modules of operations or machine-readablecode for the extraction.

By the above example construction in the extraction 308, everyexpression E on APE can be represented as a union of the minimal orcomplementary minimal sets. Accordingly, if some E on APE cannot berepresented as a union of minimal or complimentary minimal sets then itis not acceptable.

Referring to the FIG. 4 example flow diagram for the FIG. 2decomposition 116, at 310 the expression of the subject equitaggedAnnotation is found in terms of the annotations in the pre-annotateddocuments 112 that were inserted by the given annotators and aggregates102. An example expression 310 may be as follows:

-   -   a. Find the basis of the given set of annotation expressions;    -   b. Express the subject annotation as an expression on the basis;        and    -   c. Substitute each element of the basis in the expression of the        subject annotation, inserted by the subject annotator at 106 and        extant in the annotated documents 108, through the basis with        its expression through annotations inserted by the 102        annotators.

It will be understood that the above-listed example outline for carryingout the example expression 308 is only for purposes of presenting anexample expression through the basis, and is not necessarily arepresentation of a sequence, grouping or modules of operations ormachine-readable code for the expression.

Referring again to the FIG. 2 example flow diagram, after thedecomposing 116, at 118 the most suitable expression of the subjectannotation (which is an expression on the basis) is identified on a perdocument basis. Most suitable are those expressions that proved to bethe most common, i.e., have the highest frequencies of occurrence, onthe given group/corpus of documents.

At 120 that identified expression is mapped to the virtual or actualaggregate of the given annotators 102, where “virtual aggregate” meansan aggregate that does not exist in the collection of given annotatorsAnnotator_(n), but that may be created if needed, and an “actualaggregate” one the one that already exists in the collection of givenannotators 102.

An example of carrying out the above-described method, or system ifperformed on a machine reading machine-readable instruction, is asfollows:

-   -   Given: two given annotations, which we will labeled for        reference as A1 (Official_Title) and A2 (Person_Name), in the        pre-annotated documents 112, and a subject annotation, which        will be labeled for reference as A3. Also given: the following        example original text, appearing in a document in the original        document corpus 104:    -   The deal appeared to be a clear victory for Sen. John Smith,        Named Political Party, Somestate, who sponsored the proposed        bill, and a setback for Sen. Bill Murray and others who had        argued that the bill would impede United States security        efforts.

The above example original text, in the pre-annotated documents 112annotated by the annotators in 102 that implement A1 and A2, is asfollows:

-   -   The deal appeared to be a clear victory for <annot        type=“Official_Title”>Sen.</annot><annottype=“Person_Name”>John        Smith</annot>, Named Political Party-Somestate, who sponsored        the proposed bill, and a setback for <annot        type=“Official_Title”>Vice President</annot> <annot        type=“Person_Name”>Bill Murray</annot> and others who had argued        that the proposed bill would impede United States security        efforts.

The same text, in the annotated documents 108 annotated by the subjectannotator 106 that implements unknown annotation A3:

The deal appeared to be a clear victory for <annot type=“AT3”>Sen. JohnSmith </annot>, Named Political Party-Somestate, who sponsored theproposed bill, and a setback for <annot type=“AT3”>Vice President BillMurray </annot> and others who had argued that the proposed bill wouldimpede United States security efforts.

Decomposing A3 by A1 and A2, applying the decomposing 116 in accordancewith, for example, the FIG. 4 example flow diagram, we get the followingexpression:

A3=A1 union A2

Applying the described system and method, users can identify thatalready known or accessible annotators, i.e., an “annotator library,”(see, for instance, UIMA Component Repository athttp://uima.lti.cs.cmu.edu:8080/UCR/Welcome.do) that if, combined in anappropriate way to form an aggregate annotator, may meet desiredobjectives.

As described, this method and system automatically map a given subjectannotator 106 to a virtual or actual aggregate of the given annotators102. Applying the described system and method, a SAIL or other generatedannotator may be identified as functionally equivalent to, i.e., producethe same annotations as, a combination of library annotators.Accordingly, using the described system and method a rule basedannotator, generated by for example the SAIL or equivalent system, for aparticular document collection, may be replaced with a functionallyequivalent aggregate of already existing library annotators that isgenerated by the present system and method, thus significantly improvingthe overall performance of the TA application.

This in turn, may allow substituting several adjacent annotators in thegiven annotation processing pipe with one, possibly more efficient,functionally equivalent annotator from the given collection. Such asubstitution may be possible after mapping a selected group ofannotators from the given processing pipe to one of existing annotatorsfrom the given collection.

Further, the described system and method provide for selecting asuitable mapping for any group of adjacent annotators from the givenannotation processing pipe. In addition, the method and system may beapplied to extend methods of automated planning to a set of annotatorsthat include both well-known and untried ones. Automated planning isknown in the relevant art, see, for example, “Stream ProcessingPlanning”, G. Grabarnik, Z. Liu, A. Riabov, ICAPS 2005, and “Automatedplanning in the Grid stream processing environment”, G. Grabarnik, L.Shwartz, Applied Computing, 2006, so further description is unnecessaryfor applying the described system and method. Further, the system andmethod may assist or provide reduction in the dimensionality of planningproblems, such as for example, the type described in “AlgorithmOverview” section of “Automated planning in the Grid stream processingenvironment”, G. Grabarnik, L. Shwartz, Applied Computing, 2006, p. 4,and similar publications.

While certain embodiments and features of the invention have beenillustrated and described herein, many modifications, substitutions,changes, and equivalents will occur to those of ordinary skill in theart. It is therefore to be understood that the appended claims areintended to cover all such modifications and changes as fall within thespirit of the invention.

1. A computer implemented method of automatically mapping a givenannotator to an aggregate of given annotators comprising: providing aplurality of given annotators; providing aggregates of the plurality ofannotators; providing an original document corpus; applying a subjectannotator to the original document corpus to generate a corpus ofsubject annotated documents; generating a corpus of pre-annotateddocuments that contain annotations; sorting the annotations contained inthe pre-annotated documents, to generate good candidate annotations;mapping the subject annotator. 2-18. (canceled)
 19. The method of claim1, comprising: after the decomposing step, identifying, using a computeror hardware component, a suitable expression of the subject annotationon a per document basis.
 20. The method of claim 19, comprising: mappingan identified suitable expression to an aggregate of said plurality ofannotators.
 21. The method of claim 1, comprising: based on the goodcandidate annotations, decomposing the corpus of subject annotateddocuments into aggregates of the good candidate annotations.
 22. Thecomputer implemented method of claim 1, wherein the step of providingaggregates comprises providing aggregates that can be created based onconditions: (i) an input/output condition requiring compatibility at thetype system level, because annotators can be aggregated only if theyhave such compatibility; and (ii) a semantic condition, requiring thatthe annotators be such that their aggregation is meaningful.
 23. Thecomputer implemented method of claim 1, wherein the subject annotator isan unknown annotator.
 24. The computer implemented method of claim 1,wherein the subject annotator is one of the plurality of annotators. 25.The computer implemented method of claim 1, wherein the step of mappingis performed to a virtual or actual aggregate of said plurality ofannotators, where “virtual aggregate” means an aggregate that does notexist in the collection of said plurality of annotators but that may becreated if needed, and an “actual aggregate” is one that already existsin the collection of said plurality of annotators.
 26. The computerimplemented method of claim 1, comprising a decomposing step thatcomprises: modeling annotation expressions as a mapping from a corpus,document, sentence space to a span, tag space, wherein the modelingidentifies, as equitagged spans, spans with a same value of a tag, ameasure on the spans being represented as follows: Span S is representedas a union of non-intersecting intervals I_(k) from a sentenceassociated with an annotation, and for each interval I_(k)=[α_(k),α_((k+1))], where α_(i) are coordinates (positions) within the document,the measure is defined as measure m(I_(k)) being |α(k+1)−α_(k)|, and forthe span the measure is defined as m(S)=.Σm(I_(k)); embedding the spansinto a vector space of dimension greater or equal to a number of allpossible spans for a sentence; mapping an annotation expression into alattice of the possible expressions; extracting a basis on a set of allpossible expressions (APE) by choosing as the basis on the set of allpossible expressions (APE) a minimal set of elements from inclusion APE(IAPE), so that each expression E from APE may be represented as a unionof elements from IAPE; and finding an expression of the subjectequitagged Annotation in terms of the annotations in the corpus ofpre-annotated documents that were inserted by said plurality ofannotators and said aggregates of said plurality of annotators.